drivers/input/touchscreen/cyttsp4_spi.c

   1 /*
   2  * Source for:
   3  * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver.
   4  * For use with Cypress Txx4xx parts.
   5  * Supported parts include:
   6  * TMA4XX
   7  * TMA1036
   8  *
   9  * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc.
  10  * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org>
  11  * Copyright (C) 2013 Cypress Semiconductor
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * version 2, and only version 2, as published by the
  16  * Free Software Foundation.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * Contact Cypress Semiconductor at www.cypress.com <ttdrivers@cypress.com>
  24  *
  25  */
  26
  27 #include "cyttsp4_core.h"
  28
  29 #include <linux/delay.h>
  30 #include <linux/input.h>
  31 #include <linux/spi/spi.h>
  32
  33 #define CY_SPI_WR_OP            0x00 /* r/~w */
  34 #define CY_SPI_RD_OP            0x01
  35 #define CY_SPI_BITS_PER_WORD    8
  36 #define CY_SPI_A8_BIT           0x02
  37 #define CY_SPI_WR_HEADER_BYTES  2
  38 #define CY_SPI_RD_HEADER_BYTES  1
  39 #define CY_SPI_CMD_BYTES        2
  40 #define CY_SPI_SYNC_BYTE        0
  41 #define CY_SPI_SYNC_ACK         0x62 /* from TRM *A protocol */
  42 #define CY_SPI_DATA_SIZE        (2 * 256)
  43
  44 #define CY_SPI_DATA_BUF_SIZE    (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
  45
  46 static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
  47                            u8 op, u8 reg, u8 *buf, int length)
  48 {
  49         struct spi_device *spi = to_spi_device(dev);
  50         struct spi_message msg;
  51         struct spi_transfer xfer[2];
  52         u8 *wr_buf = &xfer_buf[0];
  53         u8 rd_buf[CY_SPI_CMD_BYTES];
  54         int retval;
  55         int i;
  56
  57         if (length > CY_SPI_DATA_SIZE) {
  58                 dev_err(dev, "%s: length %d is too big.\n",
  59                         __func__, length);
  60                 return -EINVAL;
  61         }
  62
  63         memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE);
  64         memset(rd_buf, 0, CY_SPI_CMD_BYTES);
  65
  66         if (reg > 255)
  67                 wr_buf[0] = op + CY_SPI_A8_BIT;
  68         else
  69                 wr_buf[0] = op;
  70         if (op == CY_SPI_WR_OP)
  71                 wr_buf[1] = reg % 256;
  72         if (op == CY_SPI_WR_OP && length > 0)
  73                 memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
  74
  75         memset(xfer, 0, sizeof(xfer));
  76         spi_message_init(&msg);
  77
  78         /*
  79           We set both TX and RX buffers because Cypress TTSP
  80           requires full duplex operation.
  81         */
  82         xfer[0].tx_buf = wr_buf;
  83         xfer[0].rx_buf = rd_buf;
  84         switch (op) {
  85         case CY_SPI_WR_OP:
  86                 xfer[0].len = length + CY_SPI_CMD_BYTES;
  87                 spi_message_add_tail(&xfer[0], &msg);
  88                 break;
  89
  90         case CY_SPI_RD_OP:
  91                 xfer[0].len = CY_SPI_RD_HEADER_BYTES;
  92                 spi_message_add_tail(&xfer[0], &msg);
  93
  94                 xfer[1].rx_buf = buf;
  95                 xfer[1].len = length;
  96                 spi_message_add_tail(&xfer[1], &msg);
  97                 break;
  98
  99         default:
 100                 dev_err(dev, "%s: bad operation code=%d\n", __func__, op);
 101                 return -EINVAL;
 102         }
 103
 104         retval = spi_sync(spi, &msg);
 105         if (retval < 0) {
 106                 dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n",
 107                         __func__, retval, xfer[1].len, op);
 108
 109                 /*
 110                  * do not return here since was a bad ACK sequence
 111                  * let the following ACK check handle any errors and
 112                  * allow silent retries
 113                  */
 114         }
 115
 116         if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK) {
 117                 dev_dbg(dev, "%s: operation %d failed\n", __func__, op);
 118
 119                 for (i = 0; i < CY_SPI_CMD_BYTES; i++)
 120                         dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n",
 121                                 __func__, i, rd_buf[i]);
 122                 for (i = 0; i < length; i++)
 123                         dev_dbg(dev, "%s: test buf[%d]:0x%02x\n",
 124                                 __func__, i, buf[i]);
 125
 126                 return -EIO;
 127         }
 128
 129         return 0;
 130 }
 131
 132 static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf,
 133                                       u8 addr, u8 length, void *data)
 134 {
 135         int rc;
 136
 137         rc = cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, NULL, 0);
 138         if (rc)
 139                 return rc;
 140         else
 141                 return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data,
 142                                 length);
 143 }
 144
 145 static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf,
 146                                        u8 addr, u8 length, const void *data)
 147 {
 148         return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data,
 149                         length);
 150 }
 151
 152 static const struct cyttsp4_bus_ops cyttsp_spi_bus_ops = {
 153         .bustype        = BUS_SPI,
 154         .write          = cyttsp_spi_write_block_data,
 155         .read           = cyttsp_spi_read_block_data,
 156 };
 157
 158 static int cyttsp4_spi_probe(struct spi_device *spi)
 159 {
 160         struct cyttsp4 *ts;
 161         int error;
 162
 163         /* Set up SPI*/
 164         spi->bits_per_word = CY_SPI_BITS_PER_WORD;
 165         spi->mode = SPI_MODE_0;
 166         error = spi_setup(spi);
 167         if (error < 0) {
 168                 dev_err(&spi->dev, "%s: SPI setup error %d\n",
 169                         __func__, error);
 170                 return error;
 171         }
 172
 173         ts = cyttsp4_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
 174                           CY_SPI_DATA_BUF_SIZE);
 175
 176         if (IS_ERR(ts))
 177                 return PTR_ERR(ts);
 178
 179         return 0;
 180 }
 181
 182 static int cyttsp4_spi_remove(struct spi_device *spi)
 183 {
 184         struct cyttsp4 *ts = spi_get_drvdata(spi);
 185         cyttsp4_remove(ts);
 186
 187         return 0;
 188 }
 189
 190 static struct spi_driver cyttsp4_spi_driver = {
 191         .driver = {
 192                 .name   = CYTTSP4_SPI_NAME,
 193                 .owner  = THIS_MODULE,
 194                 .pm     = &cyttsp4_pm_ops,
 195         },
 196         .probe  = cyttsp4_spi_probe,
 197         .remove = cyttsp4_spi_remove,
 198 };
 199
 200 module_spi_driver(cyttsp4_spi_driver);
 201
 202 MODULE_LICENSE("GPL");
 203 MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
 204 MODULE_AUTHOR("Cypress");
 205 MODULE_ALIAS("spi:cyttsp4");